Research On Characteristics And Control Methods Of Dry Friction System

On the basis of particular introduction of structure vibration control methods, the characteristics and control methods of dry friction system, such as steel cable, are analyzed detailed in this article.First, on the basis of differences between traditional ideal dry friction model and true experience, a bilinear hysteretic oscillator model is introduced, and detailed analyses about this model are given, then the delayed force is simplified by Fourier method, theoretical foundation are given for later research.Because of strong nonlinear constitute relation, the response calculation methods are noticed by many scientists. Incremental harmonic balanced method (IHB) is one of the widely used methods. Academician Prof Zhong Wan-xie presented precise integration method firstly in 1993, and ordinary differential equation can be solved precisely by this method. In this article, improved precise integration method is given firstly. Then on the basis of improved precise integration method, a new method for calculating the response of dry friction system is presented, and the calculation precise degree of this method is tested by the comparison with IHB method. It is proved that this method is a valid method of calculating the response of dry friction system. On the other hand the research about dry friction system response calculation method is limited in passive control system. In this article, the precise solution to the linear quadratic optimal control system with load is analyzed firstly, and then a gradually deduced response solution method of LQ control dry friction system is brought forward.Tendon mass damper is one of the widely used vibration control methods. It is introduced to the dry friction system. Dryfriction system with tendon mass damper is brought forward for the first time. Then the response calculation formulas of IHB method and the influence of several parameters' changing on the system response are shown in this article. Active control method is used in dry friction system at last in the third chapter. On the feedback of speed and acceleration, the active force is applied in accessory structure and main structure separately, the influence of active force is analyzed too.It is shown in experiment that dry friction system not only has bilinear hysteretic oscillator relation, but also has viscous friction and cubic restoring force, in the fifth chapter, the influence of viscous friction on response of single-freedom dry friction system and dry friction system with TMD are described, and the influence of cubic restoring force on response of single-freedom dry friction system and dry friction system with TMD are described in the sixth chapter.It the seventh chapter, the stability of dry friction system is researched. In the analyses of nonlinear vibration, the stability of movement is important besides response calculation. It is equivalent to the problem that the movement can be applied or not. On the basis that the stability of system motion can be described as the balance stability of disturbance equation, the stability problem of dry friction is studied in detail, and precise integration method is induced in the process of analyzing for improving the analyses precision. Finally, the application of IHB method in the response calculation of system with cubic restoring force is improved, and the result is more precise.